Sharif Digital Repository

Environmental conditions have a significant effect on the performance of flexible pavements. External factors such as precipitation, temperature, freeze-thaw cycles, and depth to water table play a key role in defining the extent of the impact the environment effects on pavement performance. All types of pavement distress are either caused or aggravated by the environmental factors. Up until now, pavement design in Iran is done according to the AASHTO 1993, which is based on methods that have evolved from the AASHTO Road Test that was conducted at one specific geographic location. The newly released Mechanistic Empirical Pavement Design Guide (MEPDG) by the addition of climatic input makes... 

It is widely recognized today that excess moisture in pavement layers, when combined with heavy truck traffic and moisture-susceptible materials, can reduce the service life. Temperatures below freezing can also contribute to durability problems of saturated materials. A major objective in pavement design is to keep the base, subbase, subgrade, and other susceptible paving materials from becoming saturated or even being exposed to constant high moisture levels over time. The use of subsurface drainage has gained popularity over the past two decades, and many pavement agencies now routinely specify drainable pavement structures to reduce moisture-related problems in avements. In this... 

This project aims to investigate environmental effect –such as dust and rain- on the performance of a vertical axis wind turbine (VAWT). However, those issues are frequently investigated in the horizontal axis wind turbines, but this subject has not been studied in vertical axis wind turbines. Impact of rain or dust particles on the turbine blades can change the turbine performance. So consideration of the impact of environmental factors on the performance of wind turbines is very important. Vertical axis wind turbines, particularly the straight bladed VAWT are widely used in wind power generation in agricultural and rural lighting and the use of this type of turbines is increasing... 

Precipitation in the water year 1396-1397 is the lowest in the past decade. The present study is conducted during this water year and focuses on the effects of climate variables such as temperature and precipitation on child labor supply between Tir 1397 and Farvardin 1398. Children and household characteristics are also taken into account when evaluating child labor supply using OLS and Logit methods. Estimation results indicate that both child work hours and participation in the job market decline with an increase in precipitation. Furthermore, how much time children spend working or studying is heavily influenced by parents' income. The temperature variable does not have a significant...